Ryo Katsuji is a Japanese actor and voice actor born on August 20, 1986, in Tokyo, Japan. He is a graduate of Horikoshi High School. Katsuji began his entertainment career in 2000 and has since built a career spanning live-action film, television, and voice acting for anime and dubbed foreign productions.

While primarily known for his on-screen performances, Katsuji has contributed his voice to a number of notable anime projects. In the 2006 animated film Origin: Spirits of the Past, he voiced the lead character, Agito. He also provided the voice for Descartes Shaman in the 2010 film Mobile Suit Gundam 00 The Movie: A wakening of the Trailblazer. In the television anime series Un-Go from 2011, Katsuji played the role of Shinjuro Yuki, and he later reprised this role for the 2011 prequel film Un-Go episode:0 Inga-ron. Another significant anime film role came in 2015 when he voiced Kotaro Yuda in The Case of Hana & Alice.

In addition to his work in Japanese animation, Katsuji has also worked on video game voice acting. He voiced the protagonist Nowe in the Japanese version of the 2005 game Drag-On Dragoon 2 (known internationally as Drakengard 2). His work in dubbing foreign films includes voicing Jason Scott, the Red Ranger, in the Japanese-language version of the 2017 Power Rangers movie.

For his live-action performance in the 2005 film Aegis, Katsuji was honored with the Best Newcomer Award at the 29th Japan Academy Film Prize ceremony in 2006. He is affiliated with the talent agency Foster.